The present invention relates to expansion joint construction and, more particularly, to an expansion joint spring clip that is designed as a metallic band that can eliminate flutter, pulsations and reverse bending on non-metallic fabric flue duct expansion joints.
An expansion joint is an assembly designed to safely absorb the heat-induced expansion and contraction of construction materials, to absorb vibration, to hold parts together, or to allow movement due to ground settlement or earthquakes.
Expansion joints are required in large ducted air systems to allow fixed pieces of piping to be largely free of stress as thermal expansion occurs. Expansion joints also isolate pieces of equipment, such as fans, from the rigid ductwork, thereby reducing vibration to the ductwork as well as allowing the fan to grow as it comes up to the operating air system temperature without putting stress on the fan or the fixed portions of ductwork.
There are certain conditions in flue gas and other ducting systems that require expansion joints for the relief of thermal and other movements. These systems utilize single or multiple fans to pressurize and convey the medium through the ducting system. This often introduces small amplitude, high frequency movements, known as vibrations, or somewhat higher amplitude movements, known as flutter, or very large amplitude movements as a result of pressure fluctuations, causing a reverse bending in the flexible element of the expansion joint.
These movements can lead to a separation of the layers of the expansion joint and ultimately to total failure.
Currently, devices known as flutter belts can be used to help protect an expansion joint. However, flutter belts have a lack of rigidity and only partially protect part of the entire expansion joint's width.
As can be seen, there is a need for a device that can hold an expansion joint in a fixed arch such that it can perform its function with regard to accommodating the ducting system movements, while eliminating vibrations, flutter and reverse bending.